1. Field of the Invention
The present invention generally relates to the technology of mobile communications, and more specifically to a multiple user multiple input multiple output (MU MIMO) transmission technology.
2. Description of the Prior Art
In a Long Term Evolution (LTE) Release 10 (R10) system, when a base station, that is, an evolved NodeB (eNB) adopts a setting of a 4-antenna cross-polarized antenna array, because the Release 10 codebook is not precise enough for such a setting of antennas, the effect of downlink MU MIMO is not as desirable as expected, which severely limits MU MIMO applications.